"Involvement of T cell immunity in Avian Coccidiosis"

Authors: KIM, WOO HYUN - US Department Of Agriculture (USDA); CHAUDHARI, ATUL A. - US Department Of Agriculture (USDA); Lillehoj, Hyun

Submitted to: Frontiers in Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2019
Publication Date: 11/22/2019
Citation: Kim, W., Chaudhari, A., Lillehoj, H.S. 2019. "Involvement of T cell immunity in Avian Coccidiosis". Frontiers in Immunology. https://doi.org/10.3389/fimmu.2019.02732.
DOI: https://doi.org/10.3389/fimmu.2019.02732

Interpretive Summary: Avian coccidiosis is caused by Eimeria, which is an intracellular apicomplexan parasite that invades through the intestinal tract to cause devastating disease. Host response to coccidia is very complex and there is a timely need to understand host immune response to coccidia parasites in order to develop effective control strategy against avian coccidiosis. In this paper, ARS scientists detailed the scope of complex host immune response to coccidia with emphasis on the importance of cell mediated immunity. This paper showed the important role of T-lymphocyte subpopulations, especially Th17 and Treg cells which mediate immune regulation to coccidia infection. Of particular relevance is the interplay between Treg and Th17 cells during immunoinflammatory events and the rationale on how understanding the mechanism of coccidiosis pathogenesis mediated by various T lymphocyte subpopulations can lead to logical intervention strategies to decrease the negative effects of coccidiosis. This paper will provide important information to poultry scientists including industry scientists.

Technical Abstract: Avian coccidiosis is caused by Eimeria spp. which is an intracellular apicomplexan parasite that invades through the intestinal tract to cause the overwhelming disease. Upon invasion through the intestinal epithelial cells, a strong inflammatory response is induced that results in complete villi destruction, diarrhea, hemorrhage, and in severe cases, death. Since life cycle of Eimeria parasites is complex and comprised of several intra- and, extracellular developmental stages, the host immune responses are quite diverse and complex. IFN-'-mediated Th1 response was originally considered to be the predominant immune response in avian coccidiosis. However, recent studies on other T cell lineages in chickens such as Th17 and Tregs which have been shown to have an essential role in maintaining gut homeostasis and their implication in coccidiosis, has further elucidated the role of other components of host immune response in coccidiosis. This review focuses on research findings concerning the host immune response induced by avian coccidiosis in the context of T cell immunity including the expression of T cell-related cytokines and surface molecules that determine the phenotype of T lymphocytes.